Retrieving image from SQL database

Ok, again, I'm reasonably new to this. I've been trying to display an image stored in SQL in a ASP.NET page. Pretty simple stuff I would have thought. I've read countless examples of how to do this online, and many of them use the same method of displaying the image, but none seem to work for me. The problem seems to lie in the following line of code:

Dim imageDataAsByte() =CByte(command.ExecuteScalar())

Which always returns the error: Value of type 'Byte' cannot be converted to '1-dimensional array of Byte'.

Here's the rest of my code, hope someone can help. It's doing my head in!

Imports System.Data.SqlClient

Imports System.Data

Imports System.Drawing

Imports System.IO

PartialClass _ProfileEditor

Inherits System.Web.UI.Page

ProtectedSub Page_Load(ByVal senderAsObject,ByVal eAs System.EventArgs)HandlesMe.Load

'Get the UserID of the currently logged on user

Dim NTUserIDAsString = HttpContext.Current.User.Identity.Name.ToString

Session("UserID") = NTUserID

Dim PhotoAs Image =Nothing

Dim connectionAsNew SqlConnection(ConfigurationManager.ConnectionStrings("MyConnectionString").ConnectionString)

Dim commandAs SqlCommand = connection.CreateCommand()

command.CommandText ="SELECT Photograph, ImageType FROM Users WHERE UserID = @.UserID"

command.Parameters.AddWithValue("@.UserID", NTUserID)

connection.Open()

Dim imageDataAsByte() =CByte(command.ExecuteScalar())Dim memStreamAsNew MemoryStream(Buffer)

Photo = Image.FromStream(memStream)

EndSub

EndClass

Onwww.SingingEels.com we use images (and other files like zip files, source code etc) in our database, and we show them through an ASP.NET page just like you're trying to do.

There are a few things though with the above that are an issue:

scottishfruit:

Dim imageDataAsByte() =CByte(command.ExecuteScalar())

The problem here (as your compiler is trying to tell you) is that you are trying to assign a BYTE to a BYTE_ARRAY object... to put it in human terms... a BYTE is a pair of shoes... and a BYTE_ARRAY is a shoe store... so when your friend asks you where the nearest shoe store is, and you pointed at your shoes, he yells at you :)

That's what the compiler is doing... so the long and the short of it is... you need toCAST the results from the ExecuteScalar function to a BYTE_ARRAY... like this:

Dim imageData As Byte() = CType(command.ExecuteScalar(), Byte()) <-- (I haven't done VB in a very long time, but I think that's right).

Ok, to "read" that in human speak you would say: "Create a variable named 'imageData' which happens to be an array of bytes and assign it the value of whatever comes from the fuction 'command.ExecuteScalar()' which I know is also a byte array."

I'm sure 100 people have probably posted quick answers already, but if not... let me know if this solves your problem. (or if I lost you all together)

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'hey buddy chk out these link>>>

http://aspalliance.com/articleViewer.aspx?aId=140

http://www.codeproject.com/cs/database/ImageSaveInDataBase.asp

i hope it will help u>>>

have a great day!

mark the post as answer if it helped u>>

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Awesome! That did the trick! (and your shoe analogy was pretty cool too)

Alas I now have another problem. This line:

Photo = Image.FromStream(memStream)

Is giving me this error: System.ArgumentException: Parameter is not valid.

Once again, I've googled this to pieces and there are heaps of solutions, but none that actually work!

Here's my code again:

Imports System.Data.SqlClient
Imports System.Data
Imports System.Drawing
Imports System.IO

Partial Class _ProfileEditor

Inherits System.Web.UI.Page

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

Dim NTUserID As String = HttpContext.Current.User.Identity.Name.ToString

Session("UserID") = NTUserID

Dim Photo As Image = Nothing

Dim connection As New SqlConnection(ConfigurationManager.ConnectionStrings("PeopleConnectionString").ConnectionString)

Dim command As SqlCommand = connection.CreateCommand()

command.CommandText = "SELECT Photograph, ImageType FROM Users WHERE UserID = @.UserID"

command.Parameters.AddWithValue("@.UserID", NTUserID)

connection.Open()

Dim imageData As Byte() = CType(command.ExecuteScalar(), Byte())

Dim memStream As New MemoryStream(imageData)

Photo = Image.FromStream(memStream)

End Sub

End Class

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Well, this isn't really an answer to your "what's with the argument exception" error... but I think you're almost done... there's no need to create a MemoryStream, or an Image... at this point, you already have the image data (as you so nicely named your variable)... so all that remains is for you to send that data out to the user!

scottishfruit:

Dim imageData As Byte() = CType(command.ExecuteScalar(), Byte())

Dim memStream As New MemoryStream(imageData)

Photo = Image.FromStream(memStream)

End Sub

End Class

Change the above... to this:

Dim imageData As Byte() = CType(command.ExecuteScalar(), Byte())

Response.OutputStream.Write(imageData, 0, imageData.Length)

Response.AddHeader("content-type", "image/jpeg")

Response.End()

End Sub

End Class

I know the image might not always be a JPEG... so you can leave that part out, but it's fine to use even if the image is a GIF, BMP or whatever... but if you choose to leave it out, some browsers may not appreciate that you are trying to send a picture of some kind :)

Enjoy (and when you're done... mark one of these posts as the "answer" so the thread is closed)